Managing Virtual Processors

To manage virtual processors, you need to perform the following tasks:

• Initialize VP classes
• Add and drop VPs
• Monitor VPs

Initializing a VP Class

Check your IBM Informix: Administrator's Guide and the IBM Informix: Administrator's Reference for information on VP-class initialization.

Adding and Dropping VPs

You can add or drop virtual processors in a user-defined VP class or in the CPU VP class while the database server is online. Use onmode -p to add a VP to a class or to drop a VP from a class.

The following command adds one virtual processor to the newvp class (which Figure 75 defines):

onmode -p +1 newvp

To remove a virtual processor, specify a negative value in the -p option. For more information on the onmode utility, see the IBM Informix: Administrator's Reference.

Monitoring Virtual Processors

You can use the following options on the onstat utility to monitor VPs:

• The -g glo option generates information about global multithreading such as CPU use of virtual processors and total number of sessions.
• The -g rea option generates information about the number of threads in the ready queue of the VP class.
• The -g sch option generates information about the number of semaphore operations, spins, and busy waits for each virtual processor.

A user-defined VP class appears in the onstat -g glo output as a new process. You can use the -g glo option to find the virtual process in which your DataBlade API module is loaded. Figure 79 shows the last section of the output of this onstat command.

Individual virtual processors:
 vp    pid       class       usercpu   syscpu    total
 1     11440     cpu         31.66     1.41      33.07
 2     11441     adm         0.07      0.24      0.31
 3     11442     jvp         0.04      0.05      0.09
 4     11443     lio         0.25      1.57      1.82
 5     11444     pio         0.03      0.25      0.28
 6     11445     aio         0.37      1.77      2.14
 7     11446     msc         0.00      0.04      0.04
 8     11447     aio         0.25      1.47      1.72
 9     11448     aio         0.08      0.68      0.76
 10    11449     aio         0.19      0.68      0.87
 11    11450     aio         0.15      0.46      0.61
 12    11451     aio         0.06      0.35      0.41
 13    11615     newvp       0.00      0.02      0.02
                 tot         33.15     8.99      42.14 

In Figure 79, the onstat utility displays CPU usage for the CPU VP as the first line of output. It displays the processor and CPU usage for the user-defined VP newvp, which Figure 75 defines, as the thirteenth line of output. For more information on the onstat utility, see the IBM Informix: Administrator's Reference.

In addition, you can select information from the sysvpprof SMI table about the virtual processors that are currently running. The sysvpprof SMI table exists only in the sysmaster database.